From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B764C352A1 for ; Wed, 30 Nov 2022 18:33:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230217AbiK3SdT (ORCPT ); Wed, 30 Nov 2022 13:33:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40232 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230251AbiK3SdJ (ORCPT ); Wed, 30 Nov 2022 13:33:09 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 236FA24F32 for ; Wed, 30 Nov 2022 10:33:07 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7FF6A61D67 for ; Wed, 30 Nov 2022 18:33:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B4D0C433D6; Wed, 30 Nov 2022 18:33:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669833186; bh=6IvDh34C/rgwk7a536aughaCJNLONvfI5Yuq1vZeVls=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m/LiHWmV+WQ1MqEv0wR3WADnii+zPPmssfuHHjlsYg9yGloDt/NhRHfhq5ch8DKwl VMMuXLG5UABCF0T5KBmQQigtadvJz3lqiVcWVQ+APxxugomjnE7qyM/sXSem1aSWmQ XYBBJhcF68gbKPkS3u+b47QKRT06nxY2IKr0m64Y= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sherry Sun , Sasha Levin Subject: [PATCH 5.15 005/206] tty: serial: fsl_lpuart: dont break the on-going transfer when global reset Date: Wed, 30 Nov 2022 19:20:57 +0100 Message-Id: <20221130180533.124630598@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221130180532.974348590@linuxfoundation.org> References: <20221130180532.974348590@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sherry Sun [ Upstream commit 76bad3f88750f8cc465c489e6846249e0bc3d8f5 ] lpuart_global_reset() shouldn't break the on-going transmit engine, need to recover the on-going data transfer after reset. This can help earlycon here, since commit 60f361722ad2 ("serial: fsl_lpuart: Reset prior to registration") moved lpuart_global_reset() before uart_add_one_port(), earlycon is writing during global reset, as global reset will disable the TX and clear the baud rate register, which caused the earlycon cannot work any more after reset, needs to restore the baud rate and re-enable the transmitter to recover the earlycon write. Also move the lpuart_global_reset() down, then we can reuse the lpuart32_tx_empty() without declaration. Fixes: bd5305dcabbc ("tty: serial: fsl_lpuart: do software reset for imx7ulp and imx8qxp") Signed-off-by: Sherry Sun Link: https://lore.kernel.org/r/20221024085844.22786-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/fsl_lpuart.c | 76 +++++++++++++++++++++------------ 1 file changed, 49 insertions(+), 27 deletions(-) diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index 1d13d88ea363..595430aedc0d 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -395,33 +396,6 @@ static unsigned int lpuart_get_baud_clk_rate(struct lpuart_port *sport) #define lpuart_enable_clks(x) __lpuart_enable_clks(x, true) #define lpuart_disable_clks(x) __lpuart_enable_clks(x, false) -static int lpuart_global_reset(struct lpuart_port *sport) -{ - struct uart_port *port = &sport->port; - void __iomem *global_addr; - int ret; - - if (uart_console(port)) - return 0; - - ret = clk_prepare_enable(sport->ipg_clk); - if (ret) { - dev_err(sport->port.dev, "failed to enable uart ipg clk: %d\n", ret); - return ret; - } - - if (is_imx7ulp_lpuart(sport) || is_imx8qxp_lpuart(sport)) { - global_addr = port->membase + UART_GLOBAL - IMX_REG_OFF; - writel(UART_GLOBAL_RST, global_addr); - usleep_range(GLOBAL_RST_MIN_US, GLOBAL_RST_MAX_US); - writel(0, global_addr); - usleep_range(GLOBAL_RST_MIN_US, GLOBAL_RST_MAX_US); - } - - clk_disable_unprepare(sport->ipg_clk); - return 0; -} - static void lpuart_stop_tx(struct uart_port *port) { unsigned char temp; @@ -2649,6 +2623,54 @@ static const struct serial_rs485 lpuart_rs485_supported = { /* delay_rts_* and RX_DURING_TX are not supported */ }; +static int lpuart_global_reset(struct lpuart_port *sport) +{ + struct uart_port *port = &sport->port; + void __iomem *global_addr; + unsigned long ctrl, bd; + unsigned int val = 0; + int ret; + + ret = clk_prepare_enable(sport->ipg_clk); + if (ret) { + dev_err(sport->port.dev, "failed to enable uart ipg clk: %d\n", ret); + return ret; + } + + if (is_imx7ulp_lpuart(sport) || is_imx8qxp_lpuart(sport)) { + /* + * If the transmitter is used by earlycon, wait for transmit engine to + * complete and then reset. + */ + ctrl = lpuart32_read(port, UARTCTRL); + if (ctrl & UARTCTRL_TE) { + bd = lpuart32_read(&sport->port, UARTBAUD); + if (read_poll_timeout(lpuart32_tx_empty, val, val, 1, 100000, false, + port)) { + dev_warn(sport->port.dev, + "timeout waiting for transmit engine to complete\n"); + clk_disable_unprepare(sport->ipg_clk); + return 0; + } + } + + global_addr = port->membase + UART_GLOBAL - IMX_REG_OFF; + writel(UART_GLOBAL_RST, global_addr); + usleep_range(GLOBAL_RST_MIN_US, GLOBAL_RST_MAX_US); + writel(0, global_addr); + usleep_range(GLOBAL_RST_MIN_US, GLOBAL_RST_MAX_US); + + /* Recover the transmitter for earlycon. */ + if (ctrl & UARTCTRL_TE) { + lpuart32_write(port, bd, UARTBAUD); + lpuart32_write(port, ctrl, UARTCTRL); + } + } + + clk_disable_unprepare(sport->ipg_clk); + return 0; +} + static int lpuart_probe(struct platform_device *pdev) { const struct lpuart_soc_data *sdata = of_device_get_match_data(&pdev->dev); -- 2.35.1